A typical electrical connector arrangement includes mating electrical connector components, including cylindrical plug and receptacle shells, each carrying respective electrical contacts which are moved into mating engagement by axial relative movement between the plug shell and receptacle shell. Such axial movement is produced by a coupling nut member received over the plug shell and receptacle shell which threadedly engages one of the components and axially engages the other such that upon rotation of the coupling nut member in one direction, the components are drawn together, and once the components are fully advanced into the connected state, the coupling nut member acts to retain the connector components in their connected relationship.
Disconnection is produced by backing off of the coupling nut member and separating the connector components.
In usual situations, friction in the threaded and other abutting surfaces is relied on to restrain the coupling nut member from loosening and back off once the components have been fully assembled.
In environments in which the connector assembly may be subjected to vibration, such frictional resistance to loosening of the coupling nut member may not be adequate to preclude backing off of the coupling nut member and the possibility of inadvertent separation of the electrical connector components.
Accordingly, anti-rotation devices have been incorporated in such electrical connectors, an example of such anti-rotation device disclosed in U.S. Pat. No. 4,109,990.
This patent describes an anti-rotation arrangement consisting of a spring element formed with a tooth and engaged with a series of serrations disposed about the exterior of one of the connector components. The spring is carried on the interior of the coupling nut member extending chordally across the interior bore thereof.
The engagement of the spring tooth with the serrations results in a resistance to relative rotation at force levels below that required to cam the spring tooth element out of engagement with the serrations engaged therewith. The serration profile is disclosed as being asymmetrical in order that its resistance to camming the spring tooth element out of engagement therewith is easier in one direction than the other to enable ready coupling of the connector by rotation of the coupling nut member in one direction.
The fixed position of the tooth element on the spring involved, however, makes the geometry of the serration profile critical insofar as determining turning effort, and a relatively wide variation in turning effort encountered with this design.
Application Ser. No. 101,372, filed Dec. 7, 1979, discloses another such anti-rotation arrangement including a deflectable mandrel mounted within the interior bore of the coupling nut member and chordally across the opening thereof with a clearance space between the mandrel and the outside diameter of one of the connector components. The ball element is slidably mounted on the mandrel and is located in either of two positions on either side of the clearance space and fixed stops retain the ball element in frictional engagement with the outside diameter of the connector component in either position.
Rotation of the coupling nut in one direction is resisted only by the frictional contact forces, this direction being in the direction producing coupling of the connector components. Rotation of the coupling nut member in the other direction produces a wedging effect between the sliding element and the connector component which resists rotation with much heavier force. Once a rotative force is applied sufficient to overcome the resistance presented by stiffness of the mandrel, the ball shifts to the other position with the resistance of rotation being rendered easier in the other direction of rotation which corresponds to the direction of the decoupling of the connector assembly.
In copending application Ser. No. 104,994, filed Dec. 18, 1979, there is disclosed an arrangement for increasing the frictional forces available to resist backing off of the coupling nut member as described therein to provide an anti-rotation feature between the coupling nut member and the connector components.
While generally satisfactory, efforts are constantly being applied to provide such anti-rotation features which are evermore simple and reliable in order to provide such feature for the connector which will only minimally increase manufacturing costs, while being suitable for employment in vibration environments.
It is also of course advantageous that the coupling and decoupling manipulation of the coupling nut member be enabled notwithstanding the provision of the anti-rotation features. That is, the coupling nut member must be enabled to be manipulated and rotated so as to release the connector components and such anti-rotation feature should not render this assembly difficult.
Accordingly, it is an object of the present invention to provide an anti-rotation feature for electrical connectors of the type in which the components are of a generally cylindrical configuration and which are mated by axial movement therebetween produced by a threaded coupling nut member utilized to draw the components into mating relationship and to maintain the same assembled.
It is yet another object of the present invention to provide such anti-rotation feature which is simple and reliable in operation and which the turning effort required to overcome the anti-rotation feature is accurately controlled without requiring a high degree of precision in the mating components.
It is still another object of the present invention to provide such anti-rotation feature in which the resistance to rotation of the coupling nut member in a direction corresponding to release of the connector components is much greater than in that direction corresponding to coupling of the connector components.
It is still another object of the present invention to provide such anti-rotation feature which allows the anti-rotation feature to be overcome in order to enable disassembly of the connector components.